A variable mass damper for stabilizing an on-orbit target

Abstract

This invention relates to the field of space robot research and engineering, specifically a stepless variable-mass vibration damping device for stabilizing on-orbit targets. In practical applications, it connects to an external spacecraft base and capture mechanism. It mainly comprises a structural frame assembly, a variable-mass assembly, a spring assembly, and an electrical assembly. The structural frame assembly mainly consists of several connectors, sliders, and slide rails; the variable-mass assembly mainly includes a variable-mass container, a hose, and a media tank; the spring assembly includes spring one and spring two; and the electrical assembly includes an accelerometer, a peristaltic pump, and a controller. When the stiffness of spring one and spring two, and the arithmetic square root of their ratio to the mass of the variable-mass container, equal the frequency of the axial periodic disturbance force, vibration suppression and energy transfer of the target spacecraft can be achieved. For different operating conditions, when the frequency of the external disturbance force changes, the stabilization of the on-orbit target can be achieved over a wide frequency range by steplessly adjusting the mass of the variable-mass container.

Description

Technical Field

[0001] This invention relates to the field of space robot research and engineering, specifically to a stepless variable mass vibration reduction device for stabilizing on-orbit targets. Background Technology

[0002] When a servicing spacecraft performs an on-orbit capture mission, axial contact and collisions inevitably occur between the capture mechanism and the target spacecraft due to velocity mismatch and other issues, leading to undesirable periodic vibrations in the axial direction. Furthermore, the target spacecraft itself is constantly subjected to periodic excitations from loads such as the control moment gyroscope and reaction flywheel, which impairs its pointing accuracy and affects the performance of its internal precision instruments. However, current research typically focuses only on suppressing external excitations that disturb the servicing spacecraft and its base, without investigating vibration reduction methods for the target spacecraft as the dominant vibration system. Moreover, during capture missions, the frequency of the periodic disturbance forces experienced by the target spacecraft varies due to the inherent properties of different target spacecraft and uncertainties such as the uncontrollable axial relative velocity. Therefore, to ensure the safety of the target spacecraft and suppress the negative impact of axial periodic disturbance forces on its operation, a stepless variable-mass vibration reduction device for stabilizing on-orbit targets is proposed. This device can steplessly adjust the mass parameters of its internal components under different operating conditions to stabilize the on-orbit target spacecraft within a wide range of axial disturbance force frequencies, thereby achieving stable capture. Summary of the Invention

[0003] This invention takes the case of a target spacecraft subjected to external axial excitation force after capture as its background. In order to solve the problem that the target spacecraft itself is difficult to suppress vibration and transfer energy, an axial vibration reduction device with stepless mass variation is proposed, specifically a stepless variable mass vibration reduction device for stabilizing on-orbit targets.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A stepless variable mass vibration damping device for stabilizing on-orbit targets mainly includes a structural frame assembly, a variable mass assembly, a spring assembly, and an electrical assembly.

[0006] The structural frame assembly mainly consists of a capture mechanism connecting bracket (202), a vibration damping device frame (203), a media tank mounting bracket (208), a peristaltic pump mounting bracket (210), slider one (301), slide rail one (302), slider two (303), slider three (304), slide rail two (305), and slider four (306). The variable mass assembly includes a variable mass container (205), a hose (206), and a media tank (207). The spring assembly includes spring two (204) and spring one (209). The electrical components mainly include an acceleration sensor (201), a peristaltic pump (211), and a controller (212).

[0007] Furthermore, slide rail one (302) and slide rail two (305) are respectively installed on the upper and lower inner sides of the vibration damping device frame (203). Slider one (301) and slider four (306) are respectively installed on the upper and lower outer sides of the capture mechanism connecting bracket (202), and are respectively connected to slide rail one (302) and slide rail two (305) as sliding pairs. Slider two (303) and slider three (304) are respectively installed on the upper and lower outer sides of the variable mass container (205), and are respectively connected to slide rail one (302) and slide rail two (305) as sliding pairs. The peristaltic pump (211) is fixed to the vibration damping device frame (203) through the peristaltic pump mounting bracket (210), and the medium tank (207) is fixed to the vibration damping device frame (203) through the medium tank mounting bracket (208). The two ends of the hose (206) are connected to the medium tank (207) and the variable mass container (205), respectively.

[0008] Furthermore, the variable mass container (205) comprises a container top cover (403), a container bottom cover (407), a liquid level sensor (402), a container spring one (404), a container spring two (408), a piston one (405), a piston two (406), and a container shell (401). Piston one (405) and piston two (406) both form a sliding pair with the container shell (401), allowing them to move up and down along the inner wall of the container shell (401). The container top cover (403), container bottom cover (407), liquid level sensor (402), and container shell (401) are fixedly connected. The two ends of container spring one (404) are connected to the container top cover (403) and piston one (405), respectively. The two ends of container spring two (408) are connected to the container bottom cover (407) and piston two (406), respectively. The variable mass container (205) has a vertically symmetrical structure with the axis of symmetry being a, as shown below. Figure 4 As shown.

[0009] Furthermore, the continuously variable mass vibration damping device (102) for stabilizing the on-orbit target is connected to the spacecraft base (101) or the capture mechanism (103) through the vibration damping device frame (203) or the capture mechanism connecting bracket (202), respectively. The target spacecraft (104), the spacecraft base (101) and the capture mechanism (103) are the external systems of the present invention.

[0010] Furthermore, the mass of the variable mass container (205) can be infinitely adjusted by changing the mass of the liquid medium filled in the closed space formed by piston one (405), container shell (401) and piston two (406).

[0011] Furthermore, the masses of spring 2 (204), spring 1 (209), slider 1 (301), slider 2 (303), slider 3 (304), slider 4 (306), accelerometer (201), hose (206), and controller (212) are ignored. After capture, the target spacecraft (104), capture mechanism (103), and capture mechanism connecting bracket (202) are considered as a whole, with a mass of m. t The mass of the variable mass container (205) is set to m. d The vibration damping device frame (203), medium tank (207), medium tank mounting bracket (208), peristaltic pump mounting bracket (210), peristaltic pump (211), slide rail one (302), slide rail two (305), and spacecraft base (101) are fixedly connected as a whole, with a mass of m. b Set the stiffness of spring 2 (204) to k2 and the stiffness of spring 1 (209) to k1. Target spacecraft (104) / m t The vibration displacement is x2, and the variable mass container is (205) / m. d The vibration displacement is x1.

[0012] Furthermore, assume that the axial harmonic disturbance force on the target spacecraft (104) is F = Asinωt.

[0013] Furthermore, the present invention adjusts the mass m of the variable mass container (205) d , making The frequency ω of the external excitation force is equal to the vibration displacement x2 = 0 of the target spacecraft (104), i.e., vibration suppression of the target spacecraft, and the vibration energy input by the external disturbance force is transferred to the variable mass container (205). If the frequency ω of the external harmonic disturbance force changes, the mass m of the variable mass container (205) can be continuously adjusted. d Achieve broadband adaptive vibration suppression.

[0014] The technical solution provided by this invention has the following characteristics compared with the prior art:

[0015] After the target is captured in orbit, traditional vibration suppression methods typically focus only on the disturbances caused by external excitations to the servicing spacecraft and its base, rarely considering reducing the vibration of the target spacecraft as a primary objective. Therefore, this invention, by introducing a two-degree-of-freedom undamped vibration model and a variable-mass structure, achieves vibration suppression and energy transfer of the target spacecraft under axial harmonic disturbances after capture. Furthermore, by adjusting the mass of the variable-mass container, the system parameters can be steplessly adjusted to adaptively suppress target spacecraft vibration in response to changes in external disturbances when the external excitation frequency changes. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall three-dimensional structure of a specific embodiment of the present invention;

[0017] Figure 2 A three-dimensional structural schematic diagram of the stepless variable mass vibration reduction device for stabilizing on-orbit targets according to the present invention;

[0018] Figure 3 A top view schematic diagram of the stepless variable mass vibration reduction device for stabilizing on-orbit targets according to the present invention;

[0019] Figure 4 This is a longitudinal sectional view of the variable mass container of the present invention.

[0020] Figure 5 This is an equivalent mechanical principle diagram of a specific embodiment of the present invention.

[0021] The labels in the attached diagram are explained as follows:

[0022] Spacecraft base (101), stepless variable mass vibration damping device for stabilizing on-orbit targets (102), capture mechanism (103), target spacecraft (104), acceleration sensor (201), capture mechanism connecting bracket (202), vibration damping device frame (203), spring two (204), variable mass container (205), hose (206), medium tank (207), medium tank mounting bracket (208), spring one (209), peristaltic pump mounting bracket (210), peristaltic pump (211), controller (212), slider one (301), slide rail one (302), slider two (303), slider three (304), slide rail two (305), slider four (306), container shell (401), liquid level sensor (402), container top cover (403), container spring one (404), piston one (405), piston two (406), container bottom cover (407), container spring two (408). Detailed Implementation Plan

[0023] The following is in conjunction with the appendix Figures 1-5 Further explanation of the present invention:

[0024] A stepless variable mass vibration damping device for stabilizing on-orbit targets mainly includes a structural frame assembly, a variable mass assembly, a spring assembly, and an electrical assembly.

[0025] The structural frame assembly mainly consists of a capture mechanism connecting bracket (202), a vibration damping device frame (203), a media tank mounting bracket (208), a peristaltic pump mounting bracket (210), slider one (301), slide rail one (302), slider two (303), slider three (304), slide rail two (305), and slider four (306). The variable mass assembly includes a variable mass container (205), a hose (206), and a media tank (207). The spring assembly includes spring two (204) and spring one (209). The electrical components mainly include an acceleration sensor (201), a peristaltic pump (211), and a controller (212).

[0026] Furthermore, slide rail one (302) and slide rail two (305) are respectively installed on the upper and lower inner sides of the vibration damping device frame (203). Slider one (301) and slider four (306) are respectively installed on the upper and lower outer sides of the capture mechanism connecting bracket (202), and are respectively connected to slide rail one (302) and slide rail two (305) as sliding pairs. Slider two (303) and slider three (304) are respectively installed on the upper and lower outer sides of the variable mass container (205), and are respectively connected to slide rail one (302) and slide rail two (305) as sliding pairs. The peristaltic pump (211) is fixed to the vibration damping device frame (203) through the peristaltic pump mounting bracket (210), and the medium tank (207) is fixed to the vibration damping device frame (203) through the medium tank mounting bracket (208). The two ends of the hose (206) are connected to the medium tank (207) and the variable mass container (205), respectively.

[0027] Furthermore, the variable mass container (205) comprises a container top cover (403), a container bottom cover (407), a liquid level sensor (402), a container spring one (404), a container spring two (408), a piston one (405), a piston two (406), and a container shell (401). Piston one (405) and piston two (406) both form a sliding pair with the container shell (401), allowing them to move up and down along the inner wall of the container shell (401). The container top cover (403), container bottom cover (407), liquid level sensor (402), and container shell (401) are fixedly connected. The two ends of container spring one (404) are connected to the container top cover (403) and piston one (405), respectively. The two ends of container spring two (408) are connected to the container bottom cover (407) and piston two (406), respectively. The variable mass container (205) has a vertically symmetrical structure with the axis of symmetry being a, as shown below. Figure 4As shown.

[0028] Furthermore, the continuously variable mass vibration damping device (102) for stabilizing the on-orbit target is connected to the spacecraft base (101) or the capture mechanism (103) via the vibration damping device frame (203) or the capture mechanism connecting bracket (202). The target spacecraft (104), the spacecraft base (101), and the capture mechanism (103) are external systems of the present invention.

[0029] Furthermore, the mass of the variable mass container (205) can be infinitely adjusted by changing the volume of its internal liquid medium. Specifically, the variable mass container (205) adjusts its mass through a flexible hose interface (e.g., Figure 4 The hose (206) is connected to one end of the hose (206), and the other end of the hose (206) is connected to the medium tank (207). The peristaltic pump (211) passes through the middle of the hose (206). The peristaltic pump (211) can pump the liquid medium stored in the medium tank (207) into the variable mass container (205) through the hose. The volume of the medium filled in the variable mass container (205) is the volume of the closed space formed by piston one (405), container shell (401) and piston two (406). According to the formula m v =ρ·V can be used to obtain the mass of the liquid medium in the variable mass container (205), where ρ is the density of the liquid medium and V is the volume of the liquid medium. As the amount of medium filling the variable mass container (205) gradually increases: piston one (405) moves upward along the inner wall, while piston two (406) moves downward along the inner wall, container spring one (404) and container spring two (408) are compressed, and the mass of the variable mass container (205) gradually increases; conversely, when the peristaltic pump (211) pumps the liquid medium stored in the variable mass container (205) into the medium tank (207), piston one (405) and piston two (406) move downward or upward under the action of spring force and negative pressure, respectively, container spring one (404) and container spring two (408) gradually lengthen, and the mass of the variable mass container (205) gradually decreases. Based on the above principles, by adjusting the mass of the liquid medium inside the variable mass container (205), the total mass of the variable mass container (205) can be indirectly controlled.

[0030] Furthermore, when the liquid medium in the variable mass container (205) is minimal, the distance between piston one (405) and piston two (406) is h0; when the liquid medium is abundant, the distance between piston one (405) and piston two (406) is h. 01The container springs 1 (404) and 2 (408) have the same stiffness. Therefore, pistons 1 (405) and 2 (406) always move symmetrically in opposite directions relative to the axis of symmetry a. That is, at any given moment, the displacement Δh1 of piston 1 (405) is equal to the displacement Δh2 of piston 2 (406).

[0031] Furthermore, since the masses of spring 1 (204), spring 2 (209), slider 1 (301), slider 2 (303), slider 3 (304), slider 4 (306), accelerometer (201), hose (206), and controller (212) are relatively small compared to other components, the masses of these parts are ignored. After capture, the target spacecraft (104), capture mechanism (103), and capture mechanism connecting bracket (202) are considered as a whole, with a mass of m. t The mass of the variable mass container (205) is set to m. d The vibration damping device frame (203), medium tank (207), medium tank mounting bracket (208), peristaltic pump mounting bracket (210), peristaltic pump (211), slide rail one (302), slide rail two (305), and spacecraft base (101) are fixedly connected as a whole, with a mass of m. b Set the stiffness of spring 2 (204) to k2 and the stiffness of spring 1 (209) to k1. Target spacecraft (104) / m t The vibration displacement is x2, and the variable mass container is (205) / m. d The vibration displacement is x1.

[0032] Furthermore, assume that the harmonic disturbance force experienced by the target spacecraft (104) is F = Asinωt.

[0033] Furthermore, assume m b >>m t And m b >>m d Therefore, the post-capture complex system containing the stepless variable mass vibration damping device for stabilizing on-orbit targets described in this invention can be equivalent to, for example: Figure 5 The dynamics of the two-degree-of-freedom undamped forced vibration system shown is as follows: The dynamic equations of this system can be expressed as:

[0034] Furthermore, let its particular solution be: Furthermore, we can obtain a system of non-homogeneous equations concerning amplitudes A1 and A2: Solving this equation yields the expressions for amplitudes A1 and A2: Where: f(ω) 2 )=[(k1+k2)-m d ω 2](k2-m t ω 2 )-k2 2 .

[0035] Furthermore, when At that time, it can be obtained A2 = 0. Therefore: x2 = 0. It can be seen that although the target spacecraft (104) is subjected to the disturbance force F = Asinωt, it does not vibrate, while the variable mass container (205) generates forced vibration with the same phase as the disturbance force. This is equivalent to applying the disturbance force to the variable mass container (205), while the target spacecraft (104) avoids external interference. Therefore, this invention achieves this by adjusting the mass m of the variable mass container (205). d (Essentially, it changes the mass m of the liquid medium) v ), making The frequency ω of the external disturbance force is equal to the vibration displacement x2 of the target spacecraft (104), thus achieving the design requirement that the vibration displacement x2 of the target spacecraft is equal to 0, i.e., vibration suppression of the target spacecraft, and transferring the vibration energy input by the external disturbance force to the variable mass container (205). If the frequency ω of the external harmonic disturbance force changes, the mass m of the variable mass container (205) can be continuously adjusted. d Achieve broadband adaptive vibration suppression.

[0036] Furthermore, the accelerometer (201) collects the time-domain vibration signal from one side of the target spacecraft (104) and transmits it to the controller (212). The controller (212) can convert the signal from the time domain to the frequency domain through Fourier transform, thereby obtaining the frequency ω of the vibration signal. Furthermore, the expected mass m of the variable mass container (205) can be calculated. de The peristaltic pump (211) is further controlled to adjust the capacity of the liquid medium in the variable mass container (205), thereby enabling the variable mass container (205) to reach the desired mass. During the control process, the liquid level sensor (402) can provide real-time feedback on the liquid level information inside the variable mass container (205), thus realizing closed-loop control of the desired mass.

Claims

1. A stepless variable mass vibration damping device for stabilizing an on-orbit target, comprising a structural frame assembly, a variable mass assembly, a spring assembly, and an electrical assembly, characterized in that: The structural frame assembly mainly consists of a capture mechanism connecting bracket, a vibration damping device frame, a media tank mounting bracket, a peristaltic pump mounting bracket, slider one, slide rail one, slider two, slider three, slide rail two, and slider four; the variable mass assembly includes a variable mass container, a hose, and a media tank; the spring assembly includes spring two and spring one; the electrical assembly mainly includes an acceleration sensor, a peristaltic pump, and a controller; slide rail one and slide rail two are respectively installed on the upper and lower inner sides of the vibration damping device frame; slider one and slider four are respectively installed on the upper and lower outer sides of the capture mechanism connecting bracket, and are respectively connected to slide rail one and slide rail two as sliding pairs; slider two and slider three are respectively installed on the upper and lower outer sides of the variable mass container, and are respectively connected to slide rail one and slide rail two as sliding pairs; the peristaltic pump is fixed to the vibration damping device frame through a peristaltic pump mounting bracket, and the media tank is fixed to the vibration damping device frame through a media tank mounting bracket; the two ends of the hose are respectively connected to the media tank and the variable mass container.

2. The stepless variable mass vibration damping device for stabilizing an on-orbit target according to claim 1, characterized in that: The variable mass container consists of a container top cover, a container bottom cover, a liquid level sensor, a container spring 1, a container spring 2, a piston 1, a piston 2, and a container shell. Piston 1 and piston 2 both form a sliding pair with the container shell and can move up and down along the inner wall of the container shell. The container top cover, container bottom cover, liquid level sensor, and container shell are fixedly connected. The two ends of container spring 1 are connected to the container top cover and piston 1, respectively. The two ends of container spring 2 are connected to the container bottom cover and piston 2, respectively. The variable mass container has an axisymmetric structure.

3. The stepless variable mass vibration damping device for stabilizing on-orbit targets according to claim 1, characterized in that: An accelerometer can collect time-domain vibration signals from one side of the target spacecraft and transmit them to the controller. The controller converts the time-domain signal to the frequency domain using Fourier transform, thereby obtaining the frequency of the external excitation force. When the arithmetic square root of the ratio of the sum of the stiffnesses of springs one and two to the total mass of the variable-mass container equals the external excitation frequency, the vibration displacement of the target spacecraft is zero, meaning the vibration of the target spacecraft is suppressed, and the vibration energy input by the external interference force is transferred to the variable-mass container. Based on this principle, the desired mass of the variable-mass container can be obtained. A peristaltic pump can control the flow of liquid medium between the variable-mass container and the medium tank. By adjusting the mass of the liquid medium filled inside the variable-mass container, its mass can be infinitely adjusted. When the external excitation frequency changes with factors such as the excitation source and the environment, the mass of the variable-mass container can change in real time according to the above principle to respond to the change in the external excitation frequency. A liquid level sensor can provide real-time feedback on the liquid medium capacity information inside the variable-mass container, thereby realizing closed-loop control of the mass of the variable-mass container.

4. The stepless variable mass vibration damping device for stabilizing on-orbit targets according to claim 1, characterized in that: The continuously variable mass vibration damping device for stabilizing on-orbit targets is connected to the external spacecraft base via a vibration damping device frame; the continuously variable mass vibration damping device for stabilizing on-orbit targets is connected to the external capture mechanism via a capture mechanism connecting bracket.

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